Conductor wrapping device



. WED-I) Feb. 19, 1963 w. L. OLDS ETAL 3,078,052

CONDUCTOR WRAPPING DEVICE Filed June 30. 1960 3 Sheets-Sheet 1 WILLIAML.OLDS WILLIAM J. BAKER INVENTORS.

BYWZl/W ATTORNEY Feb. 19, 1963 w. L. OLDS ETAL 3,078,052

CONDUCTOR WRAPPING DEVICE Filed June 50, 1960 3 Sheets-Sheet 2 T ig-4JNVENTORS.

WILLIAM L. OLDS i 64 42 WILLIAM J.BAKER A'I'T onus? Feb. 19, 1963 w. L.OLDS ETAL CONDUCTOR WRAPPING DEVICE 3 Sheets-Sheet 3 Filed June 30, 1960WILUAM l -.OLDS WILLIAM J. BAKER INVENTORS. W

ATTORNEY United States Patent 3,978,952 CONDUCTOR WRAPPING DEVECEWilliam L. Olds and William .F. Baker, Spring Lake, Mich, assignors toGardnenDenver iloinpany, a corporation of Delaware Filed June 3% 1960,581. No. 40,106 (llaims. Cl. 242---7) This invention relates generallyto devices for wrapping a conductor about a terminal in helicalconvolutions, and more particularly to improved wrapping bit means forsuch devices.

Devices of this general character may comprise a rotative power sourceand a shaft or bit connected to said power source and rotatablyjournaled in a stationary guide or sleeve. At its free end, the bit maybe provided with a longitudinal recess for receiving an electricalterminal and a radially-offset, longitudinally-extending groove forreceiving and positioning the end portion of a conductor which is woundabout the terminal upon rotation of the bit.

The principal object of the present invention is the provision of animproved conductor wrapping bit having a conductor engaging end faceconstructed to produce electrical connections having good electricalcharacteris tics and mechanical stability. This object is generallyattained by the provision of a wrapping bit end face having surfaceportions which continuously engage and forcibly cam stccessiveconvolutions of the conductor into high pressure contact with theterminal.

In wire Wrapping devices of this type, the last portion of the wire tobe withdrawn from the Wire-receiving groove may not be pressed inwardlytoward the terminal unless a special wipe-down surface is provided onthe bit face. Unless such a wipe-down surface is provided, undesirableinterterrninal shorting may occur between Wire ends extending laterallyfrom closely spaced terminals. Therefore, another object is to providean end face construction for a wire wrapping bit which positively andsmoothly urges the end portion of the wire into intimate contact withthe terminal.

Conductor wrapping devices sometimes employ bits having more or lessirregular end faces which, when rotated, contact the conductor in such amanner as to pro duce axial movement of the bit face with respect to thecoils of the conductor wound upon the terminal. With certainconventional end face designs, such axial movement produces impacting ofthe connection during the wrapping operation, the wipe down operationand the usual post-Wrapping turns of the bit. Such impacting may causeembrittlement of the wrapped convolutions of the conductor and tends toimpair the electrical and mechanical integrity of the connection.Therefore, in carrying out another object of this invention, the bitface construction performs the aforementioned wrapping operationswithout deleterious axial impacting of the connection. Moreparticularly, the end surface of a bit constructed in accordance withthis invention is free from sharply offset portions or other acutesurface irregulari- 'es which may produce such impacting.

Yet another object of the present invention is to overcome certaindifficulties present in conventional wrapping bits by providing a bitface construction which effectively prevents piling up or overlaying ofsuccessive conductor convolutions one upon the other. In the wrappingoperation, the conductor is coiled about the terminal in a helix. Axialforce is conventionally applied to the bit and through the bit to theconductor to insure that the convolutions of the helix are contiguous toeach other. It has been observed that excessive axial thrust applied tosome conventional bits tends to produce conductor- 3,678,052 PatentedFeb. 19, 1963 pile-up and results in a defective connection. However, inthe construction according to the present invention, that portion ofeach conductor convolution which receives the aforementioned axialthrust from the bit face is laid closely about the terminal and issecurely positioned in axial alinement with the preceding convolutionbefore axial force tending to produce pile-up is applied thereto.

A still further object is the provision of a conductor wrapping bitwhich provides the foregoing objects and advantages upon rotation of thebit in either direction. To attain this object the bit face issymmetrically constructed about a rectilinear prolongation of a diameterof the terminal receiving recess. Such flexibility in operation isparticularly advantageous in multi-bit wiring devices.

A general object is to provide a replaceable wrapping bit characterizedby ease of manufacture and low cost.

Further objects and advantages will be apparent from the followingspecification and claims read in conjunction with the accompanyingdrawings, in which:

FIGURE 1 is a view, partly in section, illustrating a rotary tool whichincludes a wrapping bit constructed in accordance with the presentinvention;

FIG. 2 is a fragmentary sectional view taken substantially along lines2-2 of FIG. 1 and illustrating a terminal disposed in the bit member inproper relationship for wrapping;

FIG. 3 is a plan view illustrating the end face of the bit member;

FIG. 4 is a fragmentary sectional View taken substantially along lines4-4 of FIG. 3;

PKG. 5 is a view similar to FIG. 3 showing the relative positions of theparts following of counter-clockwise rotation of the bit member;

FIG. 6 is a fragmentary sectional view taken substantially along lines66 of FIGURE 5;

FIG. 7 is a view similar to FIG. 3 showing the relative positions of theparts following of counter-clockwise rotation of the bit member;

FIG. 8 is a fragmentary sectional view taken substantially along lines8-8 of FIG. 7;

PEG. 9 is a View similar to FIG. 3 showing the relative positions of theparts after 270 of counter-clockwise rotation of the bit member;

FIG. 10 is a fragmentary sectional view taken substantially along lines10-10 of FIG. 9.

FIG. 11 is a transverse sectional view taken through a completed,conductor convolution wrapped about a terminal in accordance with thepresent invention;

FIG. 12 is a plan View illustrating the wipe-down of the extreme endportion of the conductor;

FIG. 13 is a View similar to FIG. 12 showing the relative positions ofthe parts following 90 of counterclockwise rotation of the bit;

FIG. 14 is a view similar to FIG. 12 showing the relative positions ofthe parts following 1-80" of counterclockwise rotation of the bit;

FIG. 15 is a view similar to FIG. 12 showing the relative positions ofthe parts following 270 of counterclockwise rotation of the bit; and,

FIG. 16 is a sectional view taken substantially alonglines 16-16 of FIG.15.

SPECIFICATION In the illustrative construction according to theinventron, the numeral it) generally indicates a rotary tool ineluding ahousing 12 for a conventional rotatable power controlled trigger element16 for manually actuating the tool. A guide sleeve 18 is detachablysecured to a forwardly projected portion of housing 12 by a nut 20. A

rotatable bit driving member 22 is coaxially carried with in guidesleeve 18 and engages a mating rotatable element (not shown) which isoperatively connected to the motor disposed in housing 12. A collet 24extends into the forward end of guide sleeve 18 and is secured againstrelative rotational and axial movement. A conductor wrapping bit 28 isinsertable into a tubular bit sleeve 30 in a forwardly direction. Inproperly assembled relation with collet 24 and bit driving member 22, asshown in FIG. 1, the bit 28 is held against relative rotation withrespect to the bit driving member 22 by interlocking engagement of a pin32, transversely carried by member 22, and a. notch in an enlarged,integral shank portion 36 of bit 28. The bit sleeve 30 is held againstrelative rotational movement with respect to collet 24 by a collet nut38 which compressively engages the bit sleeve 30 at its forward end andthreadedly engages the forwardly extending portion of collet 24. Whileabutment of the extreme inner end of bit sleeve 30 and the front face ofshank 36 of the bit prevents axial displacement of the bit 28 withrespect to sleeve 30, the shaft 40 and the integral head 42 of the bit28 are freely rotatable within the surrounding sleeve 30 in response toactuation of the motor.

As shown in FIG. 2, a bore 44 extends axially into the forward end ofbit 28. The bore 44 has a diameter and length sulficiently great tofreely receive an electrical terminal T about which conductor C is to bewound. For purposes of illustration, the terminal T is shown as agenerally rectangular metallic post; however, in practice, theconfiguration and dimensions of the terminal will vary to suitparticular wiring applications. The terminal may be fixed to a terminalboard (not shown) which carries a number of closely spaced terminals.

To position the stripped portion 48 of conductor C for application tothe terminal T in contiguous helical convolutions upon rotation of bit28, the bit is provided with a conductor receiving groove 50 which isclosed by the overlying bit sleeve 30. The groove is longitudinallyrelieved in the peripheral surface of the bit to open axially to the endface 4601? bit 28 and is disposed in radially offset relation to theterminal receiving bore or recess 44. In operation the stripped end 48of conductor C is withdrawn from groove 50 as it is wound about terminalT. In the illustrated embodiment, a portion of bit sleeve 30 whichlongitudinally projects beyond bit head 42 of the bit 28 is providedwith a pair of radially opposed slots 52 52. A selected one of theseslots receives a portion of conductor C which is first positioned in theslot and is preferably bent rearwardly along bit sleeve 30. ii

In accordance with the present invention, the illustrative wrapping bit28 is provided with an improved construction of the bit face 46 whichfacilitates production of wrapped connections characterized byincreased, uni form compression between conductor C and terminal T. Suchimproved connections are made possible by a continuous camming actionexerted upon the conductor C to successively urge each convolution intotight engagement with the terminal T and with the next precedingcompleted convolution. As will be hereinafter described in detail, thisimproved camming action is provided by a generally U-shaped cam surface68 which, during the entire Winding operation, continuously urgessuccessive portions of conductor C radially inwardly toward terminal Tand axially forwardly from the end face 46 of the bit.

As seen in FIGS. 3 and 4, for example, the end face of the bit comprisestwo axially offset, parallel flat surfaces 62 and 64 which willhereinafter be respectively referred to as the inner surface and theouter surface of the bit end face. The inner surface 62 is defined bythe peripheral edge of bit head 42, the end edge of the opening ofconductor receiving groove 50, a portion of the end edge of the openingof terminal receiving bore 44, and the inner edges of laterally spacedsurfaces 66 and 68 of cam 68. Preferably, the terminal receiving bore 44and the conductor receiving groove 50 have their entire end edges in theplane of the inner surface 62. The outer surface 64 of the bit face isdefined by the major portion of the peripheral edge of bit head 42 andthe outer edge of cam 60. The U-shaped cam 60 is interposed betweensurfaces 62 and 64 and slopingly connects these surfaces by means of thespaced surfaces 66 and 63 of the cam. A semicircular portion of theopening of bore 44 has disposed thereabout a curved portion 70 of cam 68which connects cam surfaces 66 and 68 and slopingly intersects the planeof the inner flat surface 62. The slope and width of all surfaces of cam60 are preferably uniform with respect to the plane of the inner bitface surface 62.

The aforementioned continuous camming of conductor C against terminal Tby the cam 68 will be better understood from the following descriptionof a preferred mode of operation of the tool 10. In the usual manner,the end portion 48 of conductor C is prepared and inserted apredetermined distance into groove 50; and, an adjacent insulatedportion of the conductor is bent into anchored position within aselected slot 52 and manually held along bit sleeve 30. The tool 10 isthen moved forwardly to insert the free end of terminal T into bore 44.The rotative power source housed in tool 10 is then energized forrotating bit 28 by manually depressing trigger 16. From the foregoingdescription of the parts of tool 10 and their operational relationships,it will be understood that the bit 28 and its end face 46 will rotatewithin the bit sleeve 30 and about the stationary terminal T. Looking atFIGS. 3 through 10 and assuming counter-clockwise rotation of bit 28,the stripped portion 48 of conductor C will be withdrawn from groove 50,and successive convolutions thereof will be wrapped around terminal Tuntil the extreme end of the conductor C is withdrawn and wiped down asshown in FIGS. 12 throughl6.

As thus far described, the winding operation is somewhat similar to theoperation of prior art devices for applying a conductor to a terminal.However, the following detailed description of the action of cam 60 incam' ming conductor C tightly against terminal T will point out certainessential features of the invention unattainable in prior art devices.FIGS. 3 through 10 clearly illustrate the continuous camming actionexerted against conductor C during the wrapping operation. These figuresshow progressive angular positions of cam 60, with respect to a singleconvolution of conductor C, at degree increments of counterclockwisemovement of bit 28. Spaced points, indicated by letters X, Y and Z andlocated centrally and at opposite ends of the semicircular portion 70 ofcam 60, are included in the drawings to clearly indicate the position ofthe operative camming point of cam 60 at each illustrated interval ofrevolution of bit 28 and to facilitate description of the direction ofmovement of this point along the cam surface 60. In FIGS. 3 through 10the conductor C is illustrated as having been wound around terminal Tapproximately two complete convolutions; however, it will be apparentthat the hereinafter described camming action occurs during eachwrapping revolution of the bit.

FIGS. 3 and 4 show that the stripped portion 48 of conductor C is beingdrawn from groove 50 downwardly around and to the right-hand side ofterminal T. As shown in FIG. 4, a point on the surface of strippedportion 48 engages the sloping surface of semicircular portion 70substantially at point X. Thus at this particular rotative position ofcam 60, the bottom portion 72 of the engaged convolution is being urgedradially inwardly toward the bottom surface of terminal T. At the sametime, cam 60 is urging this same portion of the convolution axiallyoutwardly against the corresponding bottom portion 74 of the nextpreceding convolution. As the cam 64 moves counter-clockwise from theposition illustrated in FIGS. 3 and 4 toward the position illustrated inFIGS. 5 and 6, the operative camming point on cam portion 7% will movein a clockwise direction from point X toward point Y as indicated by thedirectional arrow in FIG. 3. Continued counter-clockwise rotation of camto causes additional withdrawal of conductor C from groove 5% and, asshown in FIGS. 5 and 6, places camrning point Z in contact with theupper portion 76 of the instant convolution just as the bottom portion72 thereof moves axially away from the radially opposed point Y. Thedirectional arrow in FIG. 5 indicates the clockwise direction ofmovement of the operating camming point between points Z and X onsloping surface 7il. The upper portion of the instant convolution iscontinuously cammed radially inwardly and axially outwardly in themanner hereinbefore described with reference to the action of cam 66against the lower portion '72 during the preceding 90 degree incrementof revolution. After the cam tl has rotated from the angular positionillustrated in FIGS. 5 and 6 to the position shown in FIGS. 7 and 8, theoperative camming point once again becomes point X. During the next 90degrees of rotation of bit 28, the operative camming point will moveprogressively around sloping surface 70 from point X to point Ycontinuously camming the upper portion 76 of the instant convolutionagainst the upper surface of terminal T, as indicated in FIGS. 7 and 8.Just as point Y becomes inoperative for camming conductor portion 76, asshown in FIGS. 9 and 10, the operative camming point shifts from point Yto point Z. Point Z then engages the last formed bottom conductorportion '78 camming the same radially inwardly toward the lower surfaceof terminal T and axially outwardly into intimate contact with portion'72 of the next preceding convolution. As the cam 6t rotates 90 degreesin a counter-clockwise direction from the position shown in FIGS. 9 and10 to that shown in FIGS. 3 and 4, the camming point operating uponlower conductor portion 78 will travel clockwise from point Z to point Xto complete one cycle of camming action.

From the foregoing description it will be apparent that during eachcomplete revolution of the bit, the upper and lower portions of aconvolution of conductor C are alternately cammed into high pressurecontact with terminal T for 180 degree intervals of rotation. It willalso be apparent that the operative carnming points operating upon bothupper and lower portions of each convolution move progressively alongthe entire length of sloping semicircular cam surface 70 during each 180cumming period.

The importance of continuously camniing the conductor C intohigh-pressure contact with terminal '1, in accordance with thehereinbefore described operation of the invention, will be apparent tothose familiar with socalled solderless wrapped connections. A standardindustrial test employed to determine the mechanical and electricalefliciency of wrapped connections is that of applying and measuring theforce required to axially strip the wrapped convolutions of theconductor from the terminal in a direction toward the free end of theterminal. This is commonly called the strip force test. An importantadvantage of this invention is the provision of a wrapping bit whichenables tighter wrapping of a conductor about a terminal therebyincreasing the force required to strip the helically Wound conductorfrom the terminal.

The above-described Wrapping operation of the bit 2 8 which has awrapping face 46 constructed to continuously and uniformly cam theconductor radially inwardly into high pressure contact with terminal Tat the upper and lower portions of each wrap, is particularly welladapted to produce wrapped connections requiring a greater force tostrip the terminal as aforedescribed. A viewed in FIG.

11, the contacting surfaces which provide electrical conductivity andmechanical stability between conductor C and the rectangular terminal T,occur generally at upper and lower portions of each convolution of theconductor. The contacting surfaces 80 comprises mating indentations atthe sharp corners of terminal T and at spaced intervals along conductorC. Such mutual deformation is created by tensile and compressive forcesoperating upon conductor C as it is drawn around and forcibly compressedagainst terminal T by the improved wrapping bit 28. As previously shown,the semicircular cam portion 7% provides an operative camming pointwhich is continuously in contact with a portion of conductor C drawneither around the top or the bottom surface of terminal T. Thus thecritical contacting areas 80 are compressively formed by the uniformlysloping, continuously rotating cam surface 70 as the latter alternatelyoperates on the upper and lower portions of each convolution of awrapped connection. Therefore, the instant bit provides wrappedconnections between electrical conductors and terminals having a highercontacting pressure and larger total contacting area than can beobtained from bits which are constructed to provide intermittent orirregular camming action or from non-camming bits which depend solelyupon tensile forces created by drawing the conductor around the terminalto provide contact pressure.

In carrying out another important aspect of the invention; namely,prevention of conductor pile up during the wrapping operation, the axialthrust of the bit 28 against the conductor convolution being formed isimparted to a portion of the conductor C only after the latter is drawnagainst the terminal '1 into axial alinement with a lik portion of thenext preceding convolution. This objective is achieved by continuouslyproviding a space along terminal T to receive a stripped wire portion,such as port-- tion 76 in FIG. 4, as it emerges from groove 58, butbefore it is contacted by the relatively movable camming surface 76*.The space along the upper edge of terminal T into which conductorportion 76 is received, as seen in FIG. 4, is provided in the followingmanner; in response to rotation of the bit, conductor portion 72 at thebottom edge of terminal T coacts with the inclined plane of cam surface'70 to axially move the bit toward the free end of terminal T.Preferably the slope of cam surface '76 and the diameter of the strippedconductor portion 48 are so related that the axial displacement ofterminal T outwardly from here 44 per revolution of the bit is at leastone wire diameter. As the bit rotates from the position illustrated inPEG. 3 to that shown in FIG. 5, the above described space will receiveconductor portion 76 in intimate contact with the upper edge of terminalT. It will be apparent that conductor portion '76 is positioned aboutterminal T, as shown in FIG. 5, before it is acted upon by the operatingcamrning point of cam surface 70. Therefore, no axial camrning ofportion 76 occurs until that portion is wrapped closely about terminal Tin direct alinement with portion 77 of the next preceding wrappedconvolution. FIGS. 3 through 10 illustrate that the axial thrust againstthe conductor convolution being wrapped is imparted by the semicircularcarnming surface 79 at a point along the convolution which is remotefrom the opening of groove 5%. It will be seen that the inner surface 62of the face of bit 23 does not produce axial camming of the strippedconductor portion 48. Instead the axial carnming action is delayed untilthe cam surface 7i! overrides the conductor at a point angularly remotefrom the opening of groove 59, such as point Z in FIGS. 5 and 6-. Suchdelay in application of the full axial thrust of the bit 28 againstconductor C allows that portion of the convolution which later receivesthe axial thrust to be laid tightly against terminal T and in axialalinement with previously completed convolutions before any pile-upproducing thrust can be applied. It will also be apparent that theradial thrust of cam 70 against the conductor also tends to preventpile-up since the radially directed thrust component produced by cam 70holds the convolution tightly against terminal T in opposition toaxially directed forces tending to lift the convolution from terminal Tor to otherwise cause the cammed convolution to override the previouslyformed convolutions.

Another important aspect of the invention is the provision of animproved bit face construction for turning down the extreme end 82 ofthe stripped portion 48 tightly against terminal T to preventinter-terminal shorting between laterally extending conductor endportions wrapped on closely spaced terminals. Although various meanshave been devised for turning down or wiping down the end of theconductor as it emerges from the conductor re ceiving groove 50, thehereinafter described wipe-down means comprises an improved bit facewhich is especially constructed to eliminate impacting upon thecompleted convolutions of the connection during the Wipe-down operationand during post-wrapping rotations of the bit.

The improved wipe-down operation of this invention will be clearlyunderstood by referring to FIGS. 12 through 16 wherein the extreme end32 of conductor C is contacted by portions of cam 60 to neatly andfirmly lay end 82 against terminal T. As the bit rotates in acounter-clockwise direction, end 82 is withdrawn from groove 50 andslides over the inner surface 62 of the bit face into engagement with aportion 66 of sloping cam 60 as shown in FIG. 13. As camming pointsalong portion 66 and semicircular portion 70 of cam 60 progressivelyoverride end 82, the latter is cammed radially inwardly against terminalT until the end is laid against terminal T as shown in FIG. 14.Continued counter clockwise rotation of the bit to the position shown inFIG. 15 places the end 82 substantially at the conjunction of thesemicircular portion 70 and the straight portion 63 of the U-shaped cam60. Here the curved surface of end portion 32 is in moving contact withcam 60 substantially at the aforementioned point Y as seen in FIGS. 15and 16. The dimensions of conductor C, terminal T and cam 60 are sorelated that point Y occurs intermediate the width of the slopingsurface of cam 60, and is, therefore, intermediate the axially offsetsurfaces 64 and 62 of the bit face. As the cam 60 rotatescounterclockwise from the position shown in FIGS. 15 and 16, the movingpoint of contact between cam 60 and the end 82 of conductor C willtravel generally diagonally down cam portion 68 in the direction of thearrow, shown in FIG. 15, until the end 82 contacts the inner surface 62of the bit face. During each of the usual follow-up turns of the bitapplied after the wrapping operation has been completed, the end 82 willslide down cam portion 68 in the afore-described manner, engage andslide over the inner surface 62, and then engage and slide upwardlyalong cam portion 616 to a point axially intermediate the inner surface62 and the outer surface 64. As the bit rotates, the described upwardand downward sliding of the end 82 as it travels between points Y and Zproduces axial reciprocation of the bit face with respect to thestationary terminal. However, such reciprocation of the bit face willnot produce any great degree of axial impacting against the completedconnection due to the smooth travel of the bit face as it intermittentlyoverrides the completed connection along cam portions 66 and 68 of thegradually sloping cam surface 69. The resulting decrease inpost-wrapping, axial impacting upon the connection tends to preserve theoriginal level of mechanical stability between conductor C and terminalT. As thus described, the configuration of the bit face not onlyprovides high pressure contact during the formation of the connection;but also substantially eliminates post winding impacting of thecompleted connection tending to destroy its mechanical and electricalintegrity. Such improved operation is particularly advantageous inwrapping applications wherein plural connections are wrapped on a singleterminal.

Another aspect of the invention is the provision of a bit productive ofthe aforedescribed advantageous operational characteristics which may berotated in either direction to wrap a conductor about a terminal.Advanced wrapping tools equipped with reversible motor means andintended for industrial applications requiring wrapping in eitherdirection are becoming more common. There fore, a reversible wrappingbit which performs the wrapping operation equally well in eitherrotational direction is obviously more desirable than a conventionalunidirectional bit which must be replaced when reverse rotation isrequired. This object is accomplished by providing a bit face which issymmetrical about a rectilinear prolongation of a diameter of theterminal receiving bore 44. The symmetry of the bit face is clearlyshown in FIG. 3 for example. While the foregoing operational descriptionof the bit has assumed counter-clockwise rotation of the bit, it will beapparent that the camming action of the U-shaped cam 6|) with respect toconductor C would be identical in principle if the bit were rotated in aclockwise direction.

From the foregoing description of the novel bit face construction, itwill be apparent to bit users that the instant bit provides improvedwrapping features; and, it will also be appreciated by bit fabricatorsthat such bits may be manufactured entirely by simple machining operations. The symmetry and uniform slope of the previously described camsurface 60, for example, eliminate costly manufacturing operations whichhave characterized prior Wrapping bits having asymmetric cams,protruding wipe-down lugs and the like.

While the bit device has been shown and described as having particularutility when employed in hand-held, motor-actuated tools, it will beappreciated that the invention is not limited to any particular type ofwiring device. Wrapping bits of the described type are well suited foruse in automatic multi-bit wiring machines as well as in manuallyrotated tools. Since the invention resides primarily in the novel bitface configuration, many different types of special wrapping bits may beconstructed in accordance with this invention without interfering withsuch known special features as lateral loading of the conductor into thebit, combined insulation stripping and wire wrapping operations, etcetera. Moreover, it will be understood that the above description andaccompanying drawings comprehend only the general and preferredembodiment of the bit face and that various changes in the construction,proportion and arrangement of the various bit face camming surfaces maybe made without sacrificing any of the enumerated advantages of theinvention.

Having fully described the invention, we claim:

1. A device for wrapping a conductor around a terminal comprising: awrapping bit having an end face including a flat surface and cammingmeans projecting forwardly from the plane of said flat surface; said bithaving means defining a terminal receiving opening and a conductorreceiving opening both communicating with said end face and both havingtheir entire end edges in the plane of said flat surface; and saidcamming means including a curved portion disposed about said terminalreceiving opening and slopingly intersecting the plane of said flatsurface.

2. The invention according to claim 1, wherein said curved portionintersects said terminal receiving opening in the plane of said flatsurface.

3. A device for wrapping a conductor around a terminal comprising: awrapping bit having an end face including a flat surface and cammingmeans projecting for wardly from the plane of said flat surface; saidbit having means defining a terminal receiving opening and a conductorreceiving opening both communicating with said end face and both havingtheir end edges in the plane of said fiat surface; said camming meansbeing generally U-shaped and comprising laterally spaced surfaces joinedby a curved surface disposed about said terminal receiving opening; saidspaced surfaces slopingly intersecting said fiat surface, and saidcurved surface slopingly intersecting said plane.

4. The invention according to claim 3, wherein said curved portion andsaid surfaces of said camming means are uniformly sloped relative tosaid plane.

5. The invention according to claim 3, wherein said camming means issymmetrical about a prolonged diameter of said terminal receivingopening.

References Cited in the file of this patent UNITED STATES PATENTS

1. A DEVICE FOR WRAPPING A CONDUCTOR AROUND A TERMINAL COMPRISING: AWRAPPING BIT HAVING AN END FACE INCLUDING A FLAT SURFACE AND CAMMINGMEANS PROJECTING FORWARDLY FROM THE PLANE OF SAID FLAT SURFACE; SAID BITHAVING MEANS DEFINING A TERMINAL RECEIVING OPENING AND A CONDUCTORRECEIVING OPENING BOTH COMMUNICATING WITH SAID